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  View original topic: Replacing a particular K&L urethane bushing
schwim Mon Sep 15, 2014 12:25 pm

Hi there folks!

I picked up a skinny-fied beam on the classifieds here and it's clapped out pretty badly. One of the things I need to replace are the urethane beam bushings and I'm having a problem finding their replacements. It's a typical straight-tube stock custom made beam with no bearings, shoulders or anything on the inside.

The bushings I cut out are red urethane bushings with the number 3272 stamped on the outer lip. It's got a small shoulder on both the outer and inner end of the bushing. I can't find a bushing at all with this number and searching the bushings through the parts sites, I'm getting more confused with each result.

Can anyone tell me what urethane bushing would be correct for my application? I will also welcome the dictate to use Delrin bushings or stock bearings, but if someone could wedge the correct urethane bushing in between those posts, it would be greatly appreciated!

drscope Mon Sep 15, 2014 12:52 pm

There is no "correct" urethane bushing. Installing urethane is a really a corner cutting way to do an easier narrowing job.

And urethane bushing kit should work, but you aren't going to find one in the VW parts book looking up number. They are all after market stuff.

Delrin is a much better material to make these out of then urethane. So you may want to consider replacing the urethane ones you have with Delrin.

Urethane has a life of about 2 years. It gets compressed and looses shape. Oil and grease deteriorate it. Delrin is a little better. UHMW is probably best, but no one makes a readily available UHMW kit, so that would require you to have your own set machined up.

bdub475 Tue Sep 16, 2014 8:36 am

http://www.usplastic.com/mobile/item.aspx?itemid=23155&categoryid=868

Drscope. Have you used UHMW in this application or are you basing your statement on it being a better material overall? I have no experience with it and have been considering having a set made or maybe a few sets and sell a some to recoup some of my costs.

Ace Tue Sep 16, 2014 10:04 am

Urethane doesnt compress and lose it shape. But it with the wrong grease it does, and so does Delrin.

schwim Tue Sep 16, 2014 10:18 am

Thanks very much for your help guys. I ordered 45mm bushings for the beam and have picked up some di-electric grease for assembly.

bdub475 Tue Sep 16, 2014 11:54 am

I'm not saying that urethane is the best or even that good but I have over 20,000 miles on a set in my 4 inch beam and couldn't see any noticeable wear when I pulled the beam apart. They looked just like the new set I was going to replace them with. I did use di-electric grease when assembling the beam and coated it generously. I will be using delrin next time I pull it apart. But I was very surprised at their condition after reading all the bad things that have been said about then here.

drscope Tue Sep 16, 2014 5:10 pm

bdub475 wrote: http://www.usplastic.com/mobile/item.aspx?itemid=23155&categoryid=868

Drscope. Have you used UHMW in this application or are you basing your statement on it being a better material overall? I have no experience with it and have been considering having a set made or maybe a few sets and sell a some to recoup some of my costs.

I don't think I have never used UHMW in this particular application on a VW beam. However we have used it extensively on many, many suspension applications and this is one very nice material for this use.

In fact many pieces of big equipment like bulldozers and large earth movers that run in dirt, mud and abrasive environments use UHMW in many of their wheels/driveline components as bushings.

We made ALL UHMW bushings for the suspension on a 911 road race car. A-arm bushings, sway bar bushings, torsion bar bushings, etc. That car was raced EXTENSIVELY for over 12 years. An unfortunate accident at Pocono ended the car's racing career. On dis-assembly, every UHMW bushing on the car was still in great usable shape after 12 years of HARD racing! Many of those pieces were reused and are still running today on other race cars.

The biggest draw back to using the UHMW as a suspension bushing is probably going to be sound transmission into the cabin of the car. This is one of the main reasons urethane is used in the after market arena. Because urethane is a soft plastic, it doesn't transmit road noise and vibration into the chassis and cabin as much as plastics with a higher durometer reading.

For a front beam trailing arm bushing, noise and vibration transmission from UHMW shouldn't be an issue when compared to the noise and vibration transmission from the stock metal bearings. But again, I have never had a situation where I personally used UHMW in this application. It would be my first choice of materials though if I needed to crank up the lathe and make my own bushings.

ThingBeast Tue Sep 16, 2014 6:39 pm

Like Drscope said, people use tthem for a cheap fix to narrowing a beam. Do yourself a favor and get a set of micrometers and take a measurement of the ID of the tube and then go to Saco Performance and purchase a set from them.



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